The present invention relates to an improvement in an installation method of sound absorbing bodies that are attached, to prevent diffraction of noise sound, to the top portion of a sound insulation wall which is installed to prevent diffusion of noise sound generated in an expressway, a factory, etc.
A means for installing the above type of sound absorbing bodies to the top portion of a sound insulation wall is disclosed in "Improvements of Noise Reducer (Novel Sound Insulation Wall for Roads)" (in Japanese), Expressways and Automobiles, Vol. 36, No. 2, pp. 39-42, published by Express Highway Research Foundation of Japan on Feb. 1, 1993.
As shown in FIG. 8, in the above conventional means, preliminarily formed sound absorbing body halves D and E are connected to side plates B and C of an H-shaped steel member A that projects upward from the top face of a sound insulation wall (not shown) with weld bolts F and nuts G. (One of the side plates B and C faces a sound source.) Each of the sound absorbing body halves D and E is prepared in advance such that a sound absorbing material J such as glass wool is interposed between an inner sound insulation plate H such as a steel plate and an outer perforated plate I, and then a resulting structure is formed into a predetermined shape and length.
In the above conventional installation method, while the sound absorbing body halves D and E are preliminarily formed into a predetermined shape and length, in many cases the arrangement span of the H-shaped steel members A varies from one installation site to another. Where the arrangement span of the H-shaped steel members A does not conform to the length of the preliminarily formed sound absorbing body halves D and E, it is necessary to produce new sound absorbing body halves having suitable dimensions, or to adjust the length at an installation site. This results in ah increased cost, a complex installing operation, and other problems.